/*
 * buffer.c: SSH buffer
 * Copyright (C) 2018  Iru Cai <mytbk920423@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "buffer.h"
#include "ssh_endian.h"

#define INITSIZE 2048

int buffer_init(buffer *b)
{
    b->p = (uint8_t *)malloc(INITSIZE);
    if (b->p) {
        b->alloc = INITSIZE;
        b->offs = 0;
        b->sz = 0;
        return 1;
    } else {
        return 0;
    }
}

static int ensure(buffer *b, size_t len)
{
    if (b->offs + b->sz + len <= b->alloc)
        return 1;

    uint8_t *r = (uint8_t *)realloc(b->p, (b->alloc + len) * 2);
    if (r == NULL){
        return 0;
    }
    b->alloc = (b->alloc + len) * 2;
    b->p = r;

    return 1;
}

int buffer_append(buffer *b, const uint8_t *s, size_t len)
{
    if (ensure(b, len)) {
        if (s != NULL){
            memcpy(b->p + b->offs + b->sz, s, len);
        }
        b->sz += len;
        return 1;
    }

    return 0;
}

int buffer_append_string(buffer *b, const char *s, size_t len)
{
    uint32_t beint = htobe32(len);
    if (ensure(b, len + 4)) {
        *(uint32_t *)(b->p + b->offs + b->sz) = beint;
        memcpy(b->p + b->offs + b->sz + 4, s, len);
        b->sz += len + 4;
        return 1;
    } else {
        return 0;
    }
}

int buffer_append_byte(buffer *b, uint8_t x)
{
    if (ensure(b, 1)) {
        b->p[b->offs + b->sz] = x;
        b->sz += 1;
        return 1;
    } else {
        return 0;
    }
}

int buffer_append_be16(buffer *b, uint16_t x)
{
    uint16_t beint = htobe16(x);
    if (ensure(b, 2)) {
        *(uint16_t *)(b->p + b->offs + b->sz) = beint;
        b->sz += 2;
        return 1;
    } else {
        return 0;
    }
}

int buffer_append_be32(buffer *b, uint32_t x)
{
    uint32_t beint = htobe32(x);
    if (ensure(b, 4)) {
        *(uint32_t *)(b->p + b->offs + b->sz) = beint;
        b->sz += 4;
        return 1;
    } else {
        return 0;
    }
}

void buffer_get(buffer *b, uint8_t *s, size_t len)
{
    memcpy(s, buffer_data(b), len);
    buffer_consume(b, len);
}

uint8_t buffer_get_u8(buffer *b)
{
    uint8_t c = *buffer_data(b);
    buffer_consume(b, 1);
    return c;
}

uint16_t buffer_get_u16(buffer *b)
{
    uint16_t u = be16toh(*(uint16_t *)buffer_data(b));
    buffer_consume(b, 2);
    return u;
}

uint32_t buffer_get_u32(buffer *b)
{
    uint32_t u = be32toh(*(uint32_t *)buffer_data(b));
    buffer_consume(b, 4);
    return u;
}
